Phase-sensitive switch



Feb. 7, 1956 W. F. ERTZMAN ET AL PHASE-SENSITIVE SWITCH Filed April 12, 1954 40/44/444 F: 5270mm IN V EN TOR5 prroeA/is s United States Patent F PHASE-SENSITIVE SWITCH William F. Ertzman, Redondo, and Frederick J. Baumgarten, Beverly Hills, Calif., assignors to pelts Nuclear Instrument Company, Los Angeles, Calrh, a corpora tion of Nevada Application April 12, 1954, Serial No. 422,482

11 Claims. (Cl. 266-412) This invention relates to phase-sensitive devices, and, more particularly, to an improved phase-sensitive relay. A feature of this invention is the provision of a novel relay which is responsive to the difference in phase between two alternating currents, as well as to the difference in polarity of D. C. currents.

Another feature of this invention is the provision of an improved, phase-sensitive relay capable of operation at higher frequencies than heretofore possible.

Still another feature of this invention is the provision of a phase-sensitive relay which is extremely sensitive to phase diiferences.

Yet another feature of this invention is the provision of a phase-sensitive relay which is simple and inexpensive to construct.

The above features, as Well as others, are provided in an embodiment of the invention wherein a reference coil magnetizes an armature with a reference magnetic held. The armature is capable of being moved and in standby operation is positioned to be out of contact with a pair of electrodes which are positioned in the path of movement of the armature. An armature coil Winding is provided which when excited applies a field to the armature which, when it is in phase with the magnetic field applied from the reference coil, has no effect on the armature, but, when it is out of phase, causes the armature to move into contact with the electrodes positioned in its path. If desired, the reverse operation can also be achieved; that is, the contacts can be positioned so that, when the relay is excited by in-phase currents, contact is made. Contact is broken when the exciting currents are out of phase.

The novel features that are considered characteristic of this invention are set forth with particularity in the appended claims. The invention itself, both as to its organization and method of operation, as well as addi tional objects and advantages thereof, will best be understoodfrom the following description when read in connection with the accompanying drawings, in which:

Figure 1 is a front view, with cutaway portions of one embodiment of the invention;

Figure 2 is a cross section taken through Figure 1;

Figure 3 is a View in perspective of the embodiment of the invention shown in Figures 1 and 2;

Figure 4 shows an embodiment of the invention with the monitoring and armature coils in position;

Figure 5 is a front View with cutaway portions of a second embodiment of the invention; and

Figure 6 is a cross section of Figure 5.

Referring now to Figures 1, 2, and 3, there is seen one embodiment of the invention which consists of an evacuated envelope it} in substantially a U-shaped form. The envelope is made of a material which is pervious to lines of magnetic flux but which is nonconducting and nonmagnetic. A preferred material is glass. velope is hollow and contains therein an armature 16 The cn- 2,734,109 Fatented Feb. 7, 1956 which is also substantially U-shaped and coextensive with the U-shaped envelope.

As can be seen in Figures 2 and 3, the arms 12, 14 of the envelope are triangular shaped, with the base of the triangle extending at right angles to the plane of the U. At one corner of the base of the triangle in each arm there may be seen a bulb-shaped extension'18. This serves to hold a pool of mercury 20. A metal rod 22 is inserted through the envelope to extend into the mercury pool. This rod serves as the external contact. Also, in each arm, as may be seen in Figure 2, is a lid 24 to retain the mercury pool in position. By providing a small space between the end of the lid and the base of the triangle, the amount of mercury which presses against the opening between lid and base weighs less than the force exerted by the surface extension of the mercury; thereby, the relay may be tilted without having the mercury spill out of the reservoir into the rest of the evacuated envelope. In view of the construction of the relay, no harm can occur if any mercury does spill out due to any sudden jars. It can easily be spilled back into the pool.

The armature 16 is U-shaped, is made of magnetic material, and is somewhat coextensive with the envelope. It consists of a rod or crosspiece 26 which is mounted on the crosspicce of the envelope. The two arms 28, 30 of the armature may have their ends bent around the extremities of the crosspiece to permit freely swinging motion in an arc. As may be seen in Figure 2, each armature arm has a contact 32 afilxed to the end thereof, which consists of a pin fastened to the arm at one end and having the other end bent toward the mercury pool. Accordingly, when the arms of the relay are moved sulficiently the pin contact engages the mercury pool and a circuit is closed through one external contact 22, the mercury pool 26, the armature 16, the mercury pool 20, and out again through the other contact 22.

()n each envelope arm there is provided a means 36 for retaining in position a section of an armature coil. This may consist of two fiat metal strips which are crimped together and rest on the envelope near the lower end of the armatures. These metal strips are preferably made of nonmagnetic material. They are also used to hold in place magnetic cores 37. These magnetic cores serve to concentrate and focus the magnetic effect gem erated by the armature coil.

Figure 4 shows the relay with the coils in place which are required for its operation. As previously stated, the 'rmature arms can swing freely about the crosspiece. The relay is positioned so that the armature arms hang out of contact with the mercury electrodes. As shown in Figure 4, a reference coil or monitoring coil 40 is" mounted on the crosspiece of the envelope 10. The armature coil 42 consists of a single coil but is physically in two sections in series. Each section is mounted or wound on the means 36 provided therefor on each arm of the envelope. The armature coil starts and ends on the one arm. It is preferred that the Q of both armature and monitoring coils be substantially the same. The monitoring coil it) is excited from a source of potential (not shown) having either a reference phase or frequency. he armature coil 42 is excited from a source (not shown) which it is wished to monitor. If the phase or frequency of the source is the same as that of the, monitoring source, then the armature will remain in a position substantially in the center of the envelope arms and out of contact with the mercury electrode pools. Upon the source being monitored deviating either in frequency or phase from the reference source, the armature is caused to move so that the contacts engage the mercury pool and complete a circuit through the relay. The theory of operation is that when the armature and moni- 3 torcoilsvaretexcited in phase the armature, which is magnetized. when themonitor. coil is excited, finds itself. in an opposing field and is held substantially in the center of the envelope arms. When there is a phase difference betweentlre exciting currents, the field applied: by the armature coil attracts the magnetized armature to one side ofthe envelope arms. The side to which the attractionoccurs; is determinedby th'cdirection of the winding turns. .It is also; noteworthy that the relay will also operate: similarly in. response to the-application of direct current: to'opcrate in response to a diltcrence in pols of. :theapplied. direct currents.

Therelay herei'n not: only may be used. for the purpose or monitoring. to. determine phase orfrequencydilierence, but also, byipreviously'tiltingthe relay, if either the reference or' monitoring. frequency fails for some reason, ther-armsof the armature will, by gravity, be moved up to the. electrode, thus; serving as a device which can monitor the existence: of: a voltage and operate to indicate its failure. Another favored use for the apparatus is to previously tilt. the relay and. then maintain it closed by meansof two out-.ofrpha'sevoltages and, upon the failure of: the voltage: in the armature coil, the arms of the armature are moved out of contact with the mercury pool electrode in view of the previous tilt by the operation of gravity.

Referring now to Figures. 5 and 6, there is shown anothcrembodiment of the invention. This also consists ofia substantially U-shaped envelope 51, with a substantially U-shaped. coextensive. armature 52. At the ends of the -crossbar of the. envelope there are positioned two pins 54 (only one of which is shown), which serve to hold the u-shapcd armature. suspended. Atthe base of the-.envelopearmsand toone side is a bulb-shaped extension56 which contains the mercury pool S8 and a contact 60 penetrating through the envelope into the pool. The U-shaped armature 52 contains an extension rod 62 on each of the arms which extends intoextensions .64 on the envelope, which are substantially at right angles to the plane of the U. The U-shaped armature serves the same purpose as the cores- 37 in the other embodiment of the invention: namely, to. concentrate the fiux from the armature coil. The relay is positioned so that the armature hangs to the center of the envelope but out of contact with the mercury electrodes. A monitoring coil (not shown), as previously described,.is mounted at the crossbar of the U. Anarmature coil (not shown) is mounted on the. envelope extensions in the manner shown in Figure 4. As long as the phase of the exciting current in both monitor and armature: coils are substantially identical,

the. armature is magnetized in a direction to be held in the center of the field established by the armature coil. when they relative. phase of two exciting currents are opposed, the armature, is attracted toward the side of the envelope containing. the mercury pool, thus closing a circuit through the relay.

In view of the simple construction provided, it will be as phase differences of'alternating current. The contacts can "be positioned readily so that the relay is opened upon excitation with 'in-phase voltages.

'Ihere accordingly liasbeen shown and described herein anovehuseful, and simple phase-sensitive relay.

Sensitivity is. predicated upon the ease of We claim:

1. A phase-sensitive relay comprising. a U-shapedhollow envelope housing made of nonmagnetic, nonconductive material, a U-shaped armature enclosed in said envelope said armature having a crosspiece supported from said envelope and a pair of arms pivotally attached to said crosspiece, a pair ofelectrodes positioned in the path of motion of said pair of arms said electrodes including a mercury pool and a contact communicating through said envelope with said mercury pool, each of said arms includes a pin contact having one end joined to said arm and the other end pointed toward said mercury pool, means to magnctize said armature from its crosspiecewith a reference magneticfield, and means to apply a second magnetic field to said armature arms to urge them in contact with said electrodes when said second magnetic field is out of phase with said reference magnetic field.

2. A phase-sensitive relay as recited in claim 1 wherein said hollow envelope is substantially-U-shaped and said armature is substantially coextensive therewith, and said means to magnetize said armature from its crosspiecc' includes a reference coil wound over the crosspiece of said envelope.

3. A phase-sensitive relay comprising a substantially U-shaped hollow envelope made of nonmagnetic and insulating material, electrode means at one side of the arms of said U and extending through said envelope, :1 U- shaped armature for said relay made of magnetic material, said armature including a pair of arms extending intothe arms of said envelope and a crossbar portion, means supporting said armature crossbar portion in said envelope crossbar portion to permit motion of saidarmature arms in the direction at right angles to the plane of said envelope arms, means to-magnetize said armature with a'reference magnetic field, and means to establish a magnetic field about said armature arms which urges said armature'arms againstsaid electrodes when out of phase with said reference magneticfield.

4. A phase-sensitive relay comprising a substantially arms. of. said envelope and a crossbar portion, means supporting said armature crossbar portion in said envelope crossbar portion to permit motion of said armature arms in the directionat right angles to theplane of said envelope arms, a referencecoil wound over the crossbar portion of said envelope, an armature coil having two sections,

and means to support each armature. coil section on one of said envelope arms with the direction of the armature coil winding extending in the direction of' said envelope extension.

5'. A phase-sensitive relay comprising ahollowe'nv'elop'e having a crossmember and two arms extending at substantially right angles from said crossmember, aseparate electrode means extending through said envelope at one side of each arm, an armature for said relay made: of magnetic material, said armature having a pair of arms extending into the arms of said envelope adjacent said electrode means and a crossmember supported in said envelope crossmember, said armature arms being pivotally attached to said armature crossmember, meanstonmaganctize said armature with a reference magnetic field, and means to establish a magnetic field about said armature arms which urges said armature arms against said electrodes.

6. A phase-sensitive relay comprising a substantially U-shaped hollow envelope made of a nonmagnetic and insulating material, the arms of said U being broadened in a direction at right angles to the plane of" said U, electrode means at one side of the ends of said arms and extending through saidenvelope, a U-shaped armature for said relay' made of magnetic material, said armature being in said envelope and substantially coextensive therewith, means for pivotally suspending said armature at the crossbar portion of said U-shaped envelope, a reference coil wound over the crossbar portion of said U-shaped envelope, an armature coil having two sections, and means to support said armature coil sections on both arms of said envelope with the direction of said armature coil winding at right angles to the plane of said U-shaped envelope.

7. A phase-sensitive relay comprising a hollow envelope having a crossmember and two arms extending at substantially right angles from said crossmember, a separate electrode means extending through said envelope at one side of each arm, an armature for said relay made of magnetic material, said armature having a pair of arms extending into the arms of said envelope adjacent said electrode means and a crossmernber supported in said envelope crossmember, said armature arms being pivotally attached to said armature crossmember, a reference coil wound over said envelope crossmember, an armature coil. having two sections in series, and means to support each section on one of said envelope arms with the direction of the armature coil winding extending in the direction of pivotal motion of said armature arms.

8. A phase-sensitive relay as recited in claim 7 wherein each said electrode means includes a mercury pool and a contact extending through said envelope into said mercury pool.

9, A phase-sensitive relay as recited in claim 8 wherein each said armature arm includes a pointed contact member mounted on the free end of said arm and bent towards said mercury pool to make ready contact therewith when said arm is urged thereto by out-of-phase excitation of said reference and armature coils.

10. A phase-sensitive relay comprising a hollow, nonmagnetic and insulating envelope having a crossbar portion and two substantially parallel triangular shaped and coextensive arm portions extending at right angles to said crossbar portion, each of said arms having an electrode at one corner of the base of said arm, said electrode including a mercury pool and a contact extending through said envelope into said mercury pool, an armature for said relay made of magnetic material, said armature including a crossbar member supported in said crossbar member of said envelope, and a pair of arm members pivotally attached to said crossbar member and extending into said envelope arms, each said armature arm member having a contact member comprising a pin attached to and extending from the end of said arm and being bent toward said mercury electrode, a reference coil wound over said envelope crossmember, an armature coil having two sections in series, and means to support each said armature coil sections on an envelope arm with the direction of winding extending in the direction of motion of said armature arms whereby out-of-phase excitation of said reference and armature coils causes said armature arms to move.

11. A phase-sensitive relay as recited in claim 7 wherein said armature coil support means includes on each arm a pair of elongated metal straps, said straps being joined to form a close-fitting ring around said arm near the end to which said contact member is attached and a magnetic core enclosed between said elongated metal straps.

References Cited in the file of this patent UNITED STATES PATENTS 1,526,027 Traver Feb. 10, 1925 2,264,124 Schreiner Nov. 25, 1941 2,277,215 Ellwood Mar. 24, 1942 

